Modern video encoders typically compress video data for transmission to increase the amount of video-related information able to be conveyed in a given communication bandwidth. The resulting encoded video signal can then be transmitted to a receiver having a suitable video decoder capable of decompressing and/or otherwise decoding the video signal for display on an appropriate display device. Quantization is one such technique that can be used in the compression process. In video data quantization, an input range of the video data is quantized to generate a number of discrete levels such that quantized video data generally takes on fewer possible values than the input video data. As a result, quantization can reduce the precision of the video data being encoded, which can thereby reduce the number of bits required for encoding the video data.
Some video encoders are able to implement several different types of video encoding techniques, one or more of which may also have different encoding modes. For example, a video encoder can implement both intra-frame encoding, in which a pixel block of a given video frame is encoded using pixels from one or more neighboring blocks of the same frame as predictors, and inter-frame encoding, in which a pixel block of a given frame is encoded using pixels from one or more different frames as predictors. Additionally, one or both of the intra-frame and inter-frame encoding techniques employed by a video encoder may have different encoding modes corresponding to, for example, the type of block partitioning (e.g., partitioning into blocks of 16×16 pixels, 8×8 pixels, 4×4 pixels, etc.) employed by the particular encoding technique, the direction (e.g., up, left, etc.) from which pixel predictors are chosen relative to the given block to be encoded, etc. A video encoder employing different types of encoding techniques having different modes may use a cost function to calculate costs associated with the different techniques/modes to thereby permit selection of a particular encoding technique/mode having the “best” cost. Some such cost functions may also factor in other compression techniques employed by the video encoder, such as quantization, when determining the costs of the different encoding techniques/modes.
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